In an interconnected world, the defeat of international terrorism – and most importantly, the prevention of these terrorist organizations from obtaining weapons of mass destruction -- will require the cooperation of many nations. We must always reserve the right to strike unilaterally at terrorists wherever they may exist. But we should know that our success in doing so is enhanced by engaging our allies so that we receive the crucial diplomatic, military, intelligence, and financial support that can lighten our load and add legitimacy to our actions. This means talking to our friends and, at times, even our enemies.